1. Field of the Invention
The invention relates to a medical packaging material, in particular a pharmaceutical packaging material. The invention moreover relates to a method for joining of plastic components of medical packaging materials with the assistance of laser welding.
2. Description of the Related Art
It is known for thermoplastic plastics that two components can be joined with the assistance of laser welding. This is due to the fact that thermoplastic plastics have a melting phase. Thermoplastic plastics are fused through laser radiation. During cooling, the plastics combine and are fused together. Because of the low absorption of laser radiation in most thermoplastic plastics, it is however necessary that the absorption capacity of the thermoplastic plastics is improved through the addition of additives, for example color pigments or carbon black. Plastic welding with a laser by way of transmission welding whereby one or two types of thermoplastic plastics are joined with each other is known. One bonding partner is a laser-transparent plastic and another bonding partner is an absorbent plastic. With such a welding method the laser beam penetrates the upper laser-transparent base material and impinges upon the absorbent plastic below same. The laser melts the surface of the absorbent plastic. Due to the heat input, the transparent bonding partner also melts. This leads to an overlap weld. The advantage of overlap welding consists in that the welding seam in the interior of the component forms without release of any particles. A great advantage of laser welding is the local heat input.
A laser welding process for plastic materials that includes an absorber pigment and/or a scatter pigment has become known from WO 2005/100 000 A1. An infrared absorber and/or TiO2 in a concentration to 10 weight-% is described as an absorber and/or scatter pigment in WO 2005/100 000 A1. Polyethylene, preferably LDPE is utilized as plastic material. The TiO2 particles in WO 2005/100 000 A1 are scatter particles that lead to an increase of the optical path length, and via the increased optical path length to greater absorption effect. WO 2005/100 000 A1 features a laser welding process and a product that is produced in a laser welding process, however no medical packaging material, in particular no pharmaceutical packaging suitable for the high demand in regard to approval. The method according to WO 2005/100 000 A1 is also not practicable for medical packaging materials due to the absorber and/or scatter pigments.
US 2005/0224472 A1 also illustrates a laser welding process, wherein absorber and scatter pigments are utilized. These are TIO2 particles having an average particle size of 300 nm. Medical packaging materials are also not addressed in US 2005/0224472 A1.
DE 100 03 423 A1 describes a laser welding method wherein laser pigments that absorb the laser radiation are used, which leads to heating and fusing of the components that are to be joined. A medical packaging material is also not cited in DE 100 03 423 A1.
With the methods according to the state of the art, it was disadvantageous that an additive that absorbs the laser beam and partially produces heat had to be added to at least one of the plastic components that are welded with the laser.
Only certain plastics are approved for pharmaceutical packaging that generally do not contain such additives. However, through the addition of such additives the approval for the plastic to be used in pharmaceutical packaging is terminated, since the original formulation is changed, so that such a welding process generally is not considered in the field of pharmaceutical products. With medical packaging materials the use of absorber and/or scatter pigments is not possible.
Other welding methods such as ultra-welding, vibration welding, high frequency welding, and heated tool welding are inapplicable as the laser welding method for plastics in the field of medical technology, because they are associated with expensive cleaning procedures. Thus, contaminations have to be removed subsequent to welding.
It is therefore the objective of the current invention to cite a medical packaging material, in particular a pharmaceutical packaging that avoids the disadvantages of the current state of the art. In particular, a medical packaging material is to be cited whereby partial bodies are bonded through laser welding without absorber and/or scatter pigments.